The present invention relates to a surgical implant and to methods of making the same.
There are many different types of surgical implants and devices, including orthopaedic implants (hip, shoulder, knee, ankle, elbow), cranio-facial implants and spinal implants (such as a spinal cage or spinal disc). Such implants are commonly made from biocompatible metals such as titanium, titanium-based alloys, stainless steel or cobalt-chromium alloys, depending on strength and weight considerations. Another consideration, particularly for implants which replace bone, is the elastic modulus of the implant. The closer the modulus of elasticity is to natural bone, the better the stress redistribution to adjacent bone. Better stress distribution results in prolonged useful life of the implant.
To increase bonding of surrounding tissues with an implant, it is known to apply a coating to the surface of the implant, by for example plasma spraying, which roughens the surface of the implant. The coating may be of a different composition to the implant to improve wear resistance and/or to provide enhanced biocompatibility (eg. TiN is extremely inert and can be applied as a coating to aluminium- or vanadium-containing implants to prevent leaching of those metals from the implant.